Cationic quaternary ammonium compounds, both mono- and di-functional low molecular weight quaternary ammonium salts and high molecular weight polymers, are commonly employed as conditioning additives in hair care products such as shampoos, conditioners, creme rinses and setting gels to impart wet and dry combability, improve feel, enhance curl retention and impart antistatic properties to hair. The Cosmetics, Toiletries and Fragrances Association (CTFA) has established a designation index for quaternary ammonium compounds employed in cosmetic and toiletry products. Two low molecular weight quaternary ammonium compounds that are commonly used in hair-care products because of their low cost are stearylbenzyldimethylammonium chloride (CTFA designation--stearalkonium chloride) and cetyltrimethylammonium chloride (CTFA designation--cetrimonium chloride).
High molecular weight cationic quaternary ammonium polymers (polyquats) are being increasingly used in hair care products because of their reported advantages over the simple quaternary ammonium salts in enhancing wet combability, mending split ends and improving appearance. Commonly used polyquats include: Polymer JR (CTFA designation--Quaternium 19) from Union Carbide, a quaternized cellulose; Gafquat (CTFA designation--Quaternium 23) from GAF Corp., a quaternized copolymer of vinylpyrrolidone and dimethylaminoethylmethacrylate; and Merquat 100 (Quaternium 40) from Merck, a homopolymer of dimethyldiallylammonium chloride.
These quaternary ammonium conditioning additives have in common the quaternary ammonium functional group: ##STR1## Where R.sub.1 through R.sub.4 may be various substituted or unsubstituted alkyl or aryl substituents, or in the case of the polyquats, represent alkylene or arylene segments of a polymer chain. Associated with the positively charged quaternary ammonium nitrogen atom is a negatively charged counterion. This anion, X.sup.- may be a halide, hydroxide, methylsulfate or similar negatively charged group. The tetravalent bonding on the nitrogen atom in quaternary ammonium compounds imparts a formal positive charge which is maintained across a broad pH range. Quaternary ammonium compounds with hydroxide anions are classified as strong bases.
This fundamental property of quaternary ammonium compounds undoubtedly contributes to the high degree of substantivity of cationic polyquats to the electronegative surface of hair. However, this substantivity can lead to a buildup of cationic polymer on the hair during repeated use which imparts a greasy feeling and tends to attract negatively charged dust particles from the air, leading to increased soiling rates. A further disadvantage to quaternary ammonium polymers as conditioning additives in hair care products is their incompatability with the anionic surfactants and soaps commonly used in these products. These anionic compounds are usually strong acid sulfonates and tend to form insoluble complexes with the cationic quaternary ammonium compounds. This undesirable reaction often leads to the formation of a precipitate during manufacture or poor product stability during storage. We have discovered that polymers containing primary pendant amine groups of the structure: ##STR2## where: represents an organic polymer chain; and
R may be H, alkyl, aryl, --COOH, --COOR", --CONH.sub.2, etc. PA0 R=H, alkyl, aryl, --COOH, --COOR", or --CONH.sub.2, etc, and PA0 R"=methyl, ethyl or other lower alkyl; PA0 or of an ammonium salt of said amino group having the following structure (Structure II): ##STR4## where: =an organic polymer chain, PA0 R=H, alkyl, aryl, --COOH, --COOR", or --CONH.sub.2, etc. and PA0 R"=methyl, ethyl, or other lower alkyl, and PA0 .sup.- X=halide, hydroxide, methyl sulfate, or similar negatively charged group; PA0 1. Hydrolysis of a poly(N-vinylamide or imide) prepared from monomers such as N-vinyl formamide, N-vinylacetamide, N-vinylsuccinimide, N-vinyl phthalimide etc: ##STR8## 2. Hydrolysis of Poly(N-Vinyl carbamates): ##STR9## 3. A variety of reactions (Curtius, Schmidt, Lossen, Hofmann) on polyacrylic acids, amides, aminimides or acid chlorides involving formation of an intermediate polyisocyanates or direct hydrolysis of a poly(alkenyl isocyanate) to generate pendant primary amino groups of Structure I: ##STR10## Alternative routes to introduce primary amine groups of Structure I into polymers are also known that do not involve vinylamine chemistry. For example, copolymers of carbon monoxide and olefins can undergo reductive amination to generate the desired primary amino group. ##STR11## PA0 vinyl sulfonate PA0 vinylacetate PA0 acrylic acid PA0 acrylamide PA0 2-acrylamido-2-methyl propane sulfonic acid PA0 maleic anhydride
or their corresponding ammonium salts are useful in overcoming the above discussed disadvantages.